The continuing study of the nature and scope of photochemical rearrangement reactions is the subject of this proposal. Specifically, this proposal outlines studies to be completed on bicyclic beta, gamma-enones and substituent effects on their photorearrangement. Additional functional group photochemistry for monocyclic and bicyclic ring systems will be explored and developed. The synthesis of molecules where photochemical reactions serve at key stages in the synthesis are also outlined. The development of these reactions as a general route to carbocyclic and heterocyclic systems is also a major goal of the project. Parallel work on the mechanisms and the limitations of these reactions will be carried out. The project should provide new photochemical reactions of synthetic value.